I get exactly the same error message except that the procedure I followed to get it is slightly different from that described above.
I followed te tutorial at http://www.packtpub.com/article/getting-started-drupal-6-panels starting at 'Adding a custom Panels Page' (the modules had already been set up earlier).
As the description and screensots did not exactly match what I see on my computer the keystroke and mouse clicks I performed were not exactly as described. The procedure I followed was:
Administration > Panels > Add new Panel Page
- type "Test" into 'Adminstative Title' (machine name is filled in automatically)
- type "Test Panel Page" into 'Administrative description'
- type "test" into 'Path'
- click 'Continue' to go to 'Choose Layout'
- under 'Category' select 'Columns: 1'
- click the radio button above 'Single Column' to select it
- click 'Continue' to go to 'panel settings'
- click 'Continue' to go to 'Panel content' (in preparation to select 'title type')
the error message Notice: Undefined index: theme in panels_renderer_standard->render_layout() (line 382 of C:\inetpub\wwwroot\Village\drupal-7.0\modules\panels\plugins\display_renderers\panels_renderer_standard.class.php).
appears at the top of the 'Panel content' page!
I have repeated the above procedure four times. The first time I stopped before going on to the Panel Content' page, so did not get to the stage where the error message would be displyed. the other three times I completed the above procedure and got the error message on all three occasions.At no time did I click 'Finish'
If MerlinOfChaos is correct in his diagnosis of the problem, is there a fix or a workaround, or should I just ignore the error! How do I identify what is 'bad' about the layout?
I have been experimenting with Panels before going through this tutorial, though can't remember creating a Panel Page before.
I am running Drupal 7.0 with modules Panels 7.x 3.0-Alpha3, Views 7.x 3.0-Beta3 and Chaos Tools 7.x 1.0-Alpha4 and theme Danland 7.x 1.0

I may be getting on the right track to identify or possibly fix this bug!
I repeated the procedure of my previous post, but instead of 'test' I used 'test1'!
It went right through without error! I then went back (without clicking 'finish' and changed all the 'test1's back to 'test'. This again went through (to my surprise) without an error!
Going back again I saw the machine name was still 'test1' and refused to be changed back to 'test' until I saw the note telling me that once the machine name was defined it could not be changed.
So, the only difference between today and yestarday is that the machine name, yesterday, was 'test' and today it is 'test1'
My theory is this: I have been doing a lot of experimenting with drupal in recent weeks and it is highly likely that I have, in the past, created a page with the machine name 'test' (though a page with that name no longer exists in my design). Could machine name 'test' still be present in the database? and could this error message be being generated because I am trying to use machine name 'test' twice?
If someone could tell me where to look in the database I will check it out and come back to you either with a solution or more information

In an effort to clean up the many hundreds of open issues in the Panels queue, I'm going over all issues with the "Postponed, needs info" status.
As per the Panels Issue guidelines, http://drupal.org/node/573062 section 2.2, I'm closing all issues that haven't been updated during the last month.I realise that some issues will be closed, that should remain open. In these cases, most of the time, they have simply been left in the "Postponed, needs info" state by mistake.
If this is the case, and you still have an interest in this issue, please just re-open it, setting the appropriate status.

At this point I am exasperated; in a way I wish I never installed Panels as it seems that it has only caused problems on my site and to make things worse, I cannot even uninstall it because then there is a Page not found label across my home page.

I had installed Panels b/c of all the great things that were told about it in video tutorials; and indeed it has a lot of awesome potential. However, issues began to surface -- unfortunately not right away -- that made it impossible for me to actually use the functionality (I recall the inability of using the WYSIWYG editor -- causing complete code breaks, problems with AJAX, etc. it was several weeks ago).

As it just seemed to hang around not doing much I decided to uninstall it when the silly problem of the Page not found on the home page appeared. So now I reinstalled and I am getting error upon error. If I could just figure out how I can "release" the "home" page from the clutches of the Panels/Page manager....

on the home page.
EDIT: merlinofchaos -- you were right in a way: when I reinstalled the module the layout of the home page was not defined. When however I was selecting the single column layout these error came up:

Your home page is set under Configuration >> Site information and you would've probably saved yourself a lot of time if you had actually looked around a little (or seached) instead of blaming Panels. Panels didn't place that link there and has no control over it if you uninstall it.

The errors you're showing suggest a broken layout on the page, and if you were using a flexible layout that got removed when you uninstalled, I guess that's not too surprising, but I"m not sure. Typically when layouts disappear you actually just get a blank (because it has no idea how to render a layout that doesn't exist).

The inability to use the wysiwyg editor is actually wysiwyg's fault, not Panels. Thank you for blaming Panels', though. I'm sure you'll tell all your friends about it and make things even worse.

I'm sorry that you're frustrated and you've had a bad time, but taking it out on us isn't really going to get you anywhere. If you like I'll give you your money back? That's about the best I can offer.

Perhaps it would be useful if you attempted to help rather than fire sarcasm at the frustrated user.

I'm sorry, I count a lot more lines of trying to guess what the problem might be. The frustrated user is taking out his frustrations on us. That does not engender help. I'm *really* sorry you're having trouble to.

I have never seen these problems. I therefore don't know of any module that might be causing these problems. I am unable to answer the question simply, or I would do that. Taking me to task for asking a user not to take his frustrations out on me is not any more helpful.

The only thing I can tell for sure from the error messages is that there is a broken layout plugin.

If you've got some magical way for me to tell you how to fix this, I'm all ears.

I would like to add: There are a lot of people who have spread a lot of misinformation about Panels. Given that the comments contained a lot of misinformation (particularly about wysiwyg and the front page) please understand that I have a LOT of frustration about this kind of problem.

And when presented with a problem that I cannot reproduce and therefore cannot provide a simple answer for, with people yelling about how terrible the software is, yes. I react.

Sure - it's annoying when you come across things which don't work as expected - but please don't take it out on the module developers - they pour in years of their free time to give us superb free products which for the most part work very well.

Of course there will be bugs you come across which may or may not be related to the module - so report them in a nice way and the majority of people here will be only too pleased to investigate and give you a solution.

Many times I've been up shit creek - either through a module bug, or my own misunderstanding, and merlin has been quick to sort it out and help (something which he has no obligation to do, by the way!)

In terms of this problem, try setting the layout to single column to see if the problem still exists.

Good luck and don't give up with Panels - if you want to avoid learning php to theme your site, it's the best solution out there.

Hello merlin, I'm getting the same error on a upgrade I'm performing from D6 to D7.

The layout was set to Builders Layout, so I guess the custom build was lost during the upgrade process. I have tried changing the layout to one of core layouts and the error gones away but then all the panes content are also gone, my question is if there is a better method to get them back instead to have to reconfigure everything by hand?

I've just run into this problem as well. And it's a strange one. Because we have the exact same code and database running on staging and in production, where it works perfect on production but not on stage.

So, to me this seems to be something like a broken code registry, cache error or something. I will do some debugging and come back with what I find.

So, I have some more info here, not a real solution nor the root cause. But anyway...

What happens is that if you have an exported panel which happens to be overridden, your handler will look for a did (display id) to load. But if the {panels_display} table happens to be empty for whatever reason (yet to figure out), the error described above will be thrown.

It's basically this code that is instructed to look for a did which doesn't exist:

ctools_include('export'); foreach ($result as $obj) {$displays[$obj->did] = ctools_export_unpack_object('panels_display', $obj);// Modify the hide_title field to go from a bool to an int if necessary.}?>

The solution in my case was to go in and revert the panel I was dealing with, and start over with my changes.

I just had this happen in 3.3 - I created a new panel page, but I didn't pick a layout. I skipped straight to the 'content' tab in my variant, and got the error. When I went back and picked a layout, the error went away. Maybe a better error message is in order

I also had this error. I tried many things with no success. What works for me was to change jQuery version from 1.8 to 1.5 and select the development (uncompressed) for the compression level in configuration->development->jQuery update (I have the jQuery update module). Hope it helps.

Simple fix worked for me
Return to the Structure/Panels and select Edit for the panel giving error messages
Select Layout and select the same layout (you get message that you must change the layout - ignore)
Select Content and Update and Save
Then Save your changes and problem should be gone - mine was.

I think there may be several remedies for this problem. I had the exact same thing show up . . .
"Notice: Undefined index: theme in panels_renderer_standard->render_layout() (line 384 of...modules/panels/plugins/display_renderers/panels_renderer_standard.class.php)."

I tried just about everything already posted above to no avail. I repeated the steps over and over, finally a window popped up and said (this is abbreviated) and I am not good with the terminologies, I'm like a Texan studying Japanese in France. The message window said "locked by user" "would you like to unlock? warning this will take you back and your input will not be saved"
Something like that. So I said what the heck, I unlocked it and went back and recreated my panel from the beginning of where I named it and formatted it.

It worked . . . . This makes me believe that the recent release of Drupal 7 may have something that is out of sync with the panel module . . . . . or could it be the latest release of the panel module might be out of sync with the new version of Drupal 7.

I will leave it to the experts to see if they can draw anything from my nonsense. But I got nowhere until that window popped and allowed me to unlock the editor that was blocking my panel creation and format.

Hope someone can understand and relate this so that others can find a way out of this common situation. This worked for me and I spent a lot of time trying the other suggestions.

Henry YoungCreditAttribution: Henry Young commented May 29, 2014 at 7:44pm

I find that changing the panel layout, save, change it back, save. fixes the problem on a per page basis.

Being new to drupal, I used "generate content" to create the test pages (new localhost dev install). Changing themes (none customized) had no effect on the error message. As far as i know none of the themes i downloaded actually use panels. Panel Pages created manually don't display this error, so far. Using drupal 7.28, mysql 5.5.36, Microsoft-IIS/7.5 (all updates available as of 5/29/14 applied)